The present invention relates to computer systems and more particularly to initiating secure operations therein.
A link-based system topology may include multiple nodes connected by point-to-point links. The topology may not be fully connected; that is, a given node may not be directly connected to all other nodes, but any node may reach any other node via multiple links, based on configured routing mechanisms. As examples, the nodes may be a processor, an input/output (I/O) hub, or another such device.
At the outset of system operation, processor hardware is trusted to behave as specified, and link mechanisms are trusted to deliver link-layer messages sent by hardware from one link controller to another link controller. Further, the link mechanisms provide trusted information about the hardware components at each end of a link. Similarly, hardware mechanisms of the I/O hubs are trusted to behave as specified.
In certain implementations, a given protocol running on a system fabric may be used to access memory and maintain a coherent appearance and behavior of the totality of memory as a single physical address space, although separate physical memories may exist. However, this coherent behavior depends on address decoding and routing mechanisms that are configured by untrusted software. Therefore, such a protocol cannot be trusted to access memory correctly until the configuration has been validated. In particular, it cannot be trusted to be free of configuration errors and improper operations, such as memory aliases, or using the same physical address with different mappings. Thus a need exists to initiate a trusted environment in such a system.